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F = ma (First 10)
Kinematics
FMA-2007-01 · 2007 F = ma (AAPT)

2007 F = ma Exam — Question 1

1. An object moves in two dimensions according to 2 ˆ ˆ ( ) (4.0 9.0) (2.0 5.0) , r t t i t j = − + − G where r is in meters and t in seconds. When does the object cross the x-axis?
Source: Question 1, 2007 F = ma Exam, © 2007 American Association of Physics Teachers (AAPT) and the U.S. Physics Team. Adapted by PhysicsTrainer: reformatted into a separate question and answer choices for online multiple-choice practice; any shared setup from nearby questions is repeated here. Not affiliated with or endorsed by AAPT or the U.S. Physics Team.